Electromagnetic apparatus for transmitting motion from the outside to a rod-shaped member within a tubular housing



H. KUMPF 3,132,290

MOTION FROM THE BULAR HOUSING May 5, 1964 ELECTROMAGNETIC APPARATUS FOR TRANSMITTING -SHAPED MEMBER WITHIN A TU OUTSIDE TO A ROD Filed July 18, 1961 4 SheetsSheet 1 1 l 9 u 2 r m 5 p-- L v n Jaw ES "k v 1 Ehrdl 3 m AQE F L I E? 2 I i 2 m WT" m 3 s 1 sm f I I l l l l I l I IIL lul I. l I l I I Illn lllllllllll IHIOIIIIIJ I I l l I I l l I l II PIIHIIII l lll lu 1 :11.- II o 3 n54. w n. L5 6 Fig. 1

H. KUMPF RATUS FOR TRANSMITTING M SHAPED M May 5, 1964 3,132,290 OTION FROM THE ULAR HOUSING ELECTROMAGNETIC APPA OUTSIDE TO A ROD EMBER WITHIN A TUB Filed July 18, 1961 4 Sheets-Sheet 2 May 5, 1964 ELECTROMAGNETIC APPARAT OUTSIDE TO A ROD-SHAPE Filed July 18, 1961 HOIST H. KUMP US FOR TRANSMITTING MOTION FROM THE D MEMBER WITHIN A TUBULAR HOUSING 4 Sheets-Sheet 3 May 5, 1964 I H. KUMPF 3,132,290

ELECTROMAGNETIC APPARATUS FOR TRANSMITTING MOTION FROM THE OUTSIDE TO A R0 SHAPED MEMBER WITHIN A TUBULAR HOUSING Filed July 18,1961 1 4 Sheets-Sheet 4 States Patent ELECTROMAGNETIC APPARATUS FOR TRANS- My invention relates to electromagnetic apparatus for transmitting motion from the outside of a tubular housing to a rod-shaped member within the housing. Such apparatus, generally known as magnetic jack are applicable, for 'example, in nuclear techniques, preferably for controlling the lifting and lowering motion of regulating and shut-oifrods in nuclear reactors. Apparatus of this type are illustrated and described in my copending applications Serial No. 859,803, filed December 15, 1959, and

SerialNo. 8,405, filed February 12, 1960, both assigned to the assignee of the present invention.

, In a magnetic jackof the known type, the member to be displaced within the housing is fastened to a'bunchlof bendingly elastic rods of magnetizable material. An axially displaceable armature sleeve of ferromagnetic material Surrounds the bunch with clearance and forms part of-a magnetic, system that comprises a holding coil, a lifting coil and a lowering coil. The system is further provided with an auxiliary holding coil. When the holding coil or the auxiliary holding coil is electrically excited, the rods within the tubular housing are radially pulled apart from 'i one another at the height of the excited coil and are forced against the armature sleeve or the inner wall of the tubular housing, so that they are frictionally held in positions By alternately exciting the holding coils on the one hand, rand either the lifting coil or lowering coil on the other hand, the bunch oftrods is axially moved step by step. For obtaining a more uniform travel motion, the above-mentioned auxiliary holding coil can be substituted by a second complete set of holding, lifting and lowering coils. It has also been proposed toarrest rod-shaped bodies'iwithin a] tubular housing by means of clamping or knee-action mechanisms by respective armatures that reciprocate with relatively short strokes, to obtain in this manner a stepwise progressive motion of the rod-shaped bodies.

It is an object of my invention to improve magnetic-jack 1 devices and to increase theirfield of useful application by 7 doing away with the necessity of giving the movable memher a fixed full-bodied crossfsection and making it of ferromagnetic material. Another object is to permit greatly reducing the weight of the structural component that isto perform the controlled motion within the sealed tubular housing;

' to be limited to the action range of the motion-producing magnetcoil, the armature forthe holding coil is composed of a plurality of radially movable parts that jointly operate as a clamp, and the armature sleeve is coupled withthe composite armature in contour-constrained fashion.

, In such apparatus, lifting the displaceable structure is effected by alternately exciting the lifting coils and the 3,132,290- Patented May 5, 196 1 apparent from, and will be described in, the following with reference to the embodimentsof apparatus according to the invention illustrated by way of example on the accomyanying drawings in which:

FIG. 1 is a longitudinal section through a first electromagnetic apparatus along the line II in FIG. 2.

FIG. 2 is a cross section through the tubular housing portion of theapparatus along the line 11 11 in FIG. 1,

FIG. 3 shows separately the composite armature with the appertaining holding coil, the coil being in excited condition. l

FIG. 4 shows the same compositearmature in nonexcited condition of the holding coil.

FIG. 5 is an explanatory schematic, diagram relating to the lifting and lowering operation.

FIG. 6 is alongitudianl section of a second embodiment of apparatus according to-the invention.

FIG.- 7 shows in its upper portion a cross section along the line A-B in FIG. 6 and shows in its lower portion a cross section along the line C D in FIG. 6. v

FIG. 8 is a graph explanatory of a switching program for a lifting operation.

FIG. 9 is a corresponding switching program for lowering operation.

FIGS. 10, 11 and 12 are perspective views of the three components that jointly form the holding armature assembly in the device according to FIGS. 1 to 4.

FIG. 13 is a perspective view'of the lifting armature 15 in the device according to FIGS. 1 to 4; and

FIG. 14 shows a control device for energizing the magnet coils of apparatus according to the invention as requiredby the switching programs exemplified in FIGS. 8 and 9. According to FIG. 1, a rod-shaped elongated member 1, for example a regulating rod for a nuclear reactor, is surrounded on-all sides by a pressure-sealed tubular housing 2 generally of non-magnetic metal, and is guided by rollers 3 and 4 for vertical axial motion at low friction. The tubular housing 2 is concentrically surrounded by annular electromagnets, namely two holding magnets 5, 6 and two lifting magnets 7, 8 which alternate with each other longitudinally along the housing.

Correlated to each of the four electromagnets is a magnetizable armature assembly which surrounds the rod 1 within the housing 2}. The armature assembly of each holding magnet 5 and 6 consists of three individual clamping parts 9, 19, 11 (FIGS. 2, 10, 11, 12) each of which forms a ring with clearance around the rod 1. The

. respective magnetizable head pieces 12, 13 and 14 of the three clamping members are displaced 120 (FIG. 2)

from each other. The lifting arr-natures 15 and 17 which coact with the respective electromagnets 7 and 8 comprise each a magnetizablesleeve 16 or 18 (FIGS. 1, 13).

. The friction between the lifting armature'lS, 17 and the wall of housing 2 can be minimized by the provision. of glide shoes or guide rollers such as the one shown by broken lines at 3a in FIG. 1. These rollers are journalled on the housing wall in the same manner as shown for rollers 3, 4 and are in rolling engagement with the armaholding coils in a given sequence. For lowering the struct'ure the holding coils are alternately excited with conture 15. I

. Each of the two lifting armatures 15 and 17 has three upwardly protruding projections 19 (FIGS. 2, 13) spaced from each other which couple the three components /12,1il/13, 11/14 (FIGS.10, 11, 12) of the holding armature assembly with the lifting armature (FIG;

' one hand and the rod i on the other hand.

' armature inclusive of that of the rod'structure 1.

13) and which guide the three holding-armature components so that each of them can move only in a radial direction. As shown in FIG. 2 the three upward projections 3.9 of the lifting armatures 15 or 17 do not touch the inner wall of the tubular housing 2. 7

It is preferable to provide slitted sleeves 29 (FIG. 1) between the three clamping components 9, it), ill. on the Such slitted sleeves 2% reduce the peak pressure exerted at any particular locality and thus render the action of the clamping components 9, It'll, 11 more uniform. The sleeves 2t? are fastened to the respective lifting armatures l5 and 17.

The same cycle of operation is repeated with the armature l7, and so forth. During such performance a certain amount of excessive swing motion, preferably beyond the point B (FIG. 5), may occur. Generally, however, the lifting operation takes place between the points A and B.

For lowering the rod 1, the two lifting magnets 7 and 8 are he t continuously switched on. The drive functions only when the rod 1 is continuously subiected to A spring 21 seated in the tubular housing 2 and pressing against the top of the sleeve 2% acts cumulatively with respect to the weight'of the armature and pushes it reliably to the lowermost position when the lifting magnet '7 or 8 is not electrically excited. The wall of vessel 2', consisting of non-magnetic, austenitic material is provided with magnetizable rings 22'consisting preferably of ferrite and being welded between the adjacent components of the housing structure. The rings 22 form continuations of the respective magnetic field structures of the four electromagnets and hence act as pole shoes, or pole rings.

The operation of the clamping components will be explained with reference-to FIGS. 3 and 4. For simplicity, the clamping sleeve 2% is omitted and only the components 9, IZ'and lit), 13 of the holding armature assembly are shown. in FIG. 3 the holding magnet 5 is assumed to be electrically excited so that the head pieces 12 and 13 of the illustrated armature components are attracted to the pole rings 22 and clamp the rod structure ll between the clamping components 9 and it). At the points identified by black dots, the components 9 and it) firmly rest against the rod 1 and hold it in position by friction. it will be understood that the third armature component ll, 14 not shown in FIG. 3 performs the same action in a cumulative sense and, due to the uniform distribution of the three components. over the periphery, contributes to a moreuniform clamping action. It will also be understood that for some purposes the holding armature need be given only two clamping compo- I nents, whereas for other purposes more than three such components may be uniformly distributed about the structure to be moved and held. In FIG. 4 it is assumed that the holding magnet 5 is deenergized so that the armature head pieces 12 and 13 are no longerattracted toward the wall of the tubular housing 2. The rod structure 1 is now free to move in the upward or downward'direction.

The operation of the lifting magnets 7, Swill be explained with reference to FIG. 5. When the coil of the lifting magnet '7 is excited, the magnetic ring 16 is subjected to the pulling forces schematically represented in the right-hand portion ofthe diagram. G denotes the weight of the idle lifting armature and of the idle clamping components 9, lit, 11, inclusive of the sleeve 20 and the force of the spring 21. G denotes the weight of the The same forces are active upon the magnetizable ring 18 of the lifting armature l7 appertaining to the lifting magnet 3. By alternately exciting the lifting magnets '7 and 8 and the holding magnets Sand 6, a lifting motion is imparted to the rod 1. For explaining this, assume that the lifting magnet i5 and 'the holding magnet 6 are switched on and that their respective armatures hold the rod in position, while the magnets 5 and 7 are switched inertia, somewhat below this point.

a downward force, for examplegravity when the rod is in vertical or inclined position, or hydraulic force or spring force when the rod is in horizontal position. For explanation, assume that the armature 17 in coaction with the holding magnet 6 is maintaining the rod in position and that the armature l5 occupies a position corresponding to the highest point 'C'il'l FIG. 5 where the magnet 7 is in equilibrium with the weight G ofthe idle armatures inclusive of the forces of spring 21. When new the holding magnet 5 is switched on, the rod 1 becomes ied to the armature l5. Thereafter the holding magnet 6 is switched off so that the armature sleeve 18 glides into the position corresponding to point C, and the loaded armature 15 glides to the position corresponding to point B at which the forces are in equilibrium. The just-mentioned movement of armature 15 occurs because the lifting magnet 1'7 cannot hold its armature inclusiveof the rod in the position C. In practice, the rod 1 with the armature 15 drops to the position B or, for reasons of The same cycle is repeated with the other armature, and so forth. The lowering operationtherefore takes place substantially between the points C and B according to FIG. 5.

It will be understood from the foregoing, that only the unloaded armatures can abut against rigid structure when reaching their respective end positions. Such abutting of the idle armatures in the limit positions can be effectively damped by resilient stops as shown at 23 in FIG. 6. In some cases the fluid damping effective between the piston-like stop 23 and a fixed counter-abutment 23a is sufiicient. In other cases, however, aspring 23!) may be inserted. In the embodiment of FIG. 6, the lifting magnets are located above the holding magnets, and the holding armature is composed of only two clamping parts 9 and 14) and is inserted between two lateral portions 24 to form a downwardly protruding neck'of the holding armature 17 (FIG. 7);

While in FIG. 6 only one pair of magnets is shown, it is assumed that the apparatus is provided with two identical pairs of suchmagnets in the same manner as illustrated in FIG. 1 and described above. However, in both embodiments, one of the two pairs can be substituted by an auxiliary holding magnet which is to be provided with a multiple-part armature in the interior of the tubular housing, the armature cooperating with a stop that limits the armature travel in the vertical direction. Furthermore, in lieu of a motion control magnet that effects lifting and lowering, a lifting coil and a lowering coilmay be used which are directly located beside each other and which act upon a common armature sleeve whose length is limited to the action range of the two coacting coils.

. For increasing the lowering speed, the motion control coils and the holding coils can be alternately switched on and off in the same manner as during the abovedescribed lifting operation. In this. case, the lifting armatures loaded with the weight of the rod, do not drop to the mid-position corresponding to point B in FIG. 5, but drop down to the lowermost limiting stops. This, however, involves the disadvantage that the apparatus no longer operates free of impact and that appreciable frictional wear at the rod may occur.

In apparatus according to the invention, as exemplified by the embodiments described above, the rod structure to be moved is tied by frictional connection to the holding armature and the latter in turn is suspended by means of the lifting armature only by the action of magnetic lines of force. For that reason, a frictional gliding of the cam shaft relative to the motor shaft.

ment of the cam shaft is controlled by two electromagnets 'rod 1 in the sleeve 20 or in the'clamping components of the holding armature does not occur to an appreciable 1 extent when the magnet components are given a suitable dimensioning; The cross section of the rod structure can-be given any desired design.

Most advantageous are circular or ring-shaped cross sections. Thus, the component may consist of a tubular member as shown in FIG. 1, which permits greatly reducingthe massand weightnof the member.

smaller weight than with the conventional magnetic jack devices. As a result the overall dimensions of the entire apparatus can also be reduced and the required forces are correspondingly 'smalL' When the holding magnets or all magnets are deenergized, the rod 1 drops without 7 hindrance as is desirable for shut-01f or scram performance in nuclear reactor plants. Diagrammatically illus-.

'trated in FIGS. 8 and 9 are the switching programs for lifting and lowering operations as described above. Represented by heavy vertical lines is the switching-on duration of the individual magnet'coils which are identi 'fiedin the horizontal direction of the abscissa by respective numbers.

. The circuit diagram shown in FIG; 14 mass a 7 switching device that permits, energizing and deenergizing I the magnet coils 5; to 8 in accordance with the switching programs'for lifting and lowering operations shown in FIGS. Sand 9. The energizing circuits according to FIG, 14 are connected to a direct-voltage supply by a main switch-MS. When closing a motor control switch MC, a direct-current motor M is put into operation at aspeed adjustable by means of a field control rheostat SC; A cam shaft" with four cam bodies C to C is coupled with the shaft of motor M by means of a sleeve 28 fastened to the cam shaft and provided with two pairs of slots "or grooves that extend parallel to thesleeve a'x'is'and are engaged by cross pins or keys 29. of the motor shaft so as to permit axial displacement of the Such displace- EM and EM which can be alternately energized under i control by two switches LS and HS ganged together with each other.

The two magnets have a common armature linked to a lever 25 that is pivoted at 26 and engages at 27 a ring located between two discs firmly mounted on v the cam shaft. Shifting the lever 25 in one or the other direction by excitation of a selected one of the two magnets causes the cam shaft to be axially shifted accordrespective followers 30 for actuating four respective switchesS to S in the energizing circuits of the respective electromagnet coils 5 to 8.

-At the switching stage shown in FIG. 14, with the cam shaft rotating as indicated by an arrow, the switches S and 8,; are just moved to closed positions and the switches S and S to the open positions. The cam bodies C and C are angularly displaced from each vother to a slight extent so that the switch S closes shortly prior to closing of switch S Consequently, the holding magnet 6 becomes energized a short interval of time earlier than the lifting magnet 8. At the moment when switch S is being closed, the switches S and S are being opened. The cams C and C are likewise displaced angularly from each other so that the holding magnet 5 is switched on shortly ahead of the lifting magnet 7. Furthermore,

taneously. opening'the switch HS, the electromagnet EM is energized and the cam shaft is displaced towardthe right. --"As a xresult, the cam followers for switches-S and S cooperate with the circular contours c of cams'C and'Cg so that the holding .coils 7 and 8 remain can:

tinuously switched on, whereas the switches S and'S are alternately opened and'closed. Now the lifting and holding coils are energized in accordance with the switching program of FIG. 9,' and the rod structure is being lowered. It is preferable to connect the circular cam contour c and the lobed contour b on each of cams C and C by a curved or inclined transitional" area so that the cam follower 30 can smoothly glide from one contour to the other when the-camshaft is being axially shifted.

It will be obvious to those skilled in the art, upon studying this disclosure, that my invention permits, of various modificationswith respect to structural details and hence can be given embodiments other than'particularly illustrated and described herein, without departing from-the essential featuresof my invention andwithin the scope of the claims annexed hereto.

- I claim:

1. Electromagnetic apparatus" for imparting motion from the outside to 'a rod structure within a housing, comprising a tubular housing and an elongated rod structure axially displaceable in said housing, respective moving and holding armature means surrounding said. rod structure inside said housing, said moving armature means being axially reciprocable a given distance and having a biasing force tending to move it in one direction, motion control electromagnet means surrounding the housing for moving said moving armature means in the other direction when energized, holding electromagnet means surrounding the housing, said holding armature means having a plurality of clamping parts angularly displaced from one another about the axis of said rod structure and surrounding said rod structure with clearance when said holding electromagnetic means are deenergized, said parts being attractable outwardly by said holding electromagnetic means when the latter is energized to then clamp said rod structure, said'moving armature means being engageable to said holding armature means to move together in the other direction, whereby said magnets can be periodically energized to progressively shift'said rod structure in said housing.

2. Electromagnetic apparatus for imparting motion from the outside to a rod structure within a housing, comprising a'tubular housing and an elongated rod structure axially displaceable in said housing, a plurality of sets of electromagnets around said housing and comprising each a motion control magnet and a holding magnet having respective movingv and holding armature means surrounding said rod structure inside said housing, each of said moving armature means being axially reciprocable a given distance and having a biasing force tending to move it in one direction, said respective motion control magnets moving said moving armature means axially in the other direction when said corresponding electromagnetic means are energized, each of said holding armature means having a plurality of clamping parts angularly displaced from one another about the axis of said rod structure and surrounding'said rod structure with clearance attractable outwardly by said corresponding holding magnet when the latter'is energized to then clamp said sleeve moving together in the other direction.

3. Electromagnetic apparatus 1 for imparting motion from the outside to a rod structure within a housing,

comprising a tubular housing and an elongated rod struc-' ture axially displaceable in said housing, said housing and rod structure extending in an upward direction, a plurality of sets of axially sequential electromagnets disposed around said housing, each set having a single motion control magnet for lifting and lowering said rod structure and having a single holding magnet, said two magnets having respective first and second armature means surrounding said rod structure inside said housing, said first armature means being axially reciprocable a given distance and having a biasing force tending to move it in one direction, said second armature means being movable I by said first armature meansso asto move'together with saidfirst' armature means in the other direction when said motion control magnet isenergized, said second armature means having a plurality of clamping parts angularly displaced from one another about the axis of .said rod structure and surrounding said rod :structure with clearance when said holding magnet is deenergized, said parts being attractable outwardly by said holding magnet when the latter is energized to then clamp said rod structure in position.

4. Electromagnetic apparatus according to claim 1,

comprising a radially compressible clamping sleeve coaxially mounted between said rod structure and said clamping parts of said second armature means and forming a part of said moving armature means; 7

5. In electromagnetic apparatus according to claim 1, said holding armature means comprising a total of three of said clamping parts having respective segmental head portions 120 displaced from each other, each clamping part having at least one loop portion extending from said head portion around said rod structure.

6. In electromagnetic apparatus according to claim 2,

each of said clamping parts having a head portion an- 8 gularly spaced from that of the adjacent clamping part and having at least one loopportion extending from said loop portion around said rod structure, and an armature sleeve having. projections extending substantially parallel to the sleeve axis between said head portions for radially guiding said clamping parts.

7. Electromagnetic apparatus according to claim 2, comprising respective longitudinally slitted clamping sleeves for each set of electromagnets, said sleeves being coaxially seated on said rod structure and being axially displaceable relative to said rod structure when said clamping sleeve is relaxed, said clamping sleeves'being anchored to said moving armature means to axially move together therewith and being surrounded by said clamping parts to be radially compressed thereby for frictionally engaging said rod structure when said holding magnet is energized. a

8. Electromagnetic apparatus according to claim 1, comprising annular stop mem ers mounted in said housing around said rod structure for limiting axial motion of said armature means, said stop members being axially displaceble within'a given range, and spring means engaging said stop 'members to permit axially yielding displacement thereof.

9. Electromagnetic apparatus according to claim 2, comprising current supply means, a switching device for energizing said electromagnets from said supply means and having lifting control means alternately connecting said motion control magnets and said holding magnets to said'supply means for lifting said rod structure, and lowering control means connecting said supply means continuously to said motion control magnets and intermittentlyto said' holding magnets for lowering said rod structure.

I References Cited in the file of this patent UNITED STATES PATENTS Pollak May 3, 1960 Handshuhet al July 6, 1961 Bates July 16, 1962 

1. ELECTROMAGNETIC APPARATUS FOR IMPARTING MOTION FROM THE OUTSIDE TO A ROD STRUCTURE WITHIN A HOUSING, COMPRISING A TUBULAR HOUSING AND AN ELONGATED ROD STRUCTURE AXIALLY DISPLACEABLE IN SAID HOUSING, RESPECTIVE MOVING AND HOLDING ARMATURE MEANS SURROUNDING SAID ROD STRUCTURE INSIDE SAID HOUSING, SAID MOVING ARMATURE MEANS BEING AXIALLY RECIPROCABLE A GIVEN DISTANCE AND HAVING A BIASING FORCE TENDING TO MOVE IT IN ONE DIRECTION, MOTION CONTROL ELECTROMAGNET MEANS SURROUNDING THE HOUSING FOR MOVING SAID MOVING ARMATURE MEANS IN THE OTHER DIRECTION WHEN ENERGIZED, HOLDING ELECTROMAGNET MEANS SURROUNDING THE HOUSING, SAID HOLDING ARMATURE MEANS HAVING A PLURALITY OF CLAMPING PARTS ANGULARLY DISPLACED FROM ONE ANOTHER ABOUT THE AXIS OF SAID ROD STRUCTURE AND SURROUNDING SAID ROD STRUCTURE WITH CLEARANCE WHEN SAID HOLDING ELECTROMAGNETIC MEANS ARE DEENERGIZED, SAID PARTS BEING ATTRACTABLE OUTWARDLY BY SAID HOLDING ELECTROMAGNETIC MEANS WHEN THE LATTER IS ENERGIZED TO THEN CLAMP SAID ROD STRUCTURE, SAID MOVING ARMATURE MEANS BEING ENGAGEABLE TO SAID HOLDING ARMATURE MEANS TO MOVE TOGETHER IN THE OTHER DIRECTION, WHEREBY SAID MAGNETS CAN BE PERIODICALLY ENERGIZED TO PROGRESSIVELY SHIFT SAID ROD STRUCTURE IN SAID HOUSING. 